The invention relates to a sharpener for pencils with a soft lead with a sharpener housing, which has a conical sharpener channel, with a sharpening knife, which is fastened at the sharpener housing and is set tangentially to the sharpener channel, and with a shape-cutting knife, which can be swiveled into the sharpener channel, is provided with a manually actuated lever and is provided with an arc-shaped, curved cutting edge for the selective profiling of the front end section of the lead.
In the case of such a sharpener, which is described in the German patent 37 37 863 C1, the shape-cutting knife is mounted at a plug, which can be pressed from below into a recess of the sharpener housing. This construction has the disadvantage that, on the one hand, the downward opening, out of which normally the sharpening waste falls, is largely closed off by this plug and, on the other, that the sharpener housing must have a complex surface formation with lateral bulges, in order to form a bearing part for the pivotable carrier of the shape-cutting knife.
It is therefore an object of the invention to configure a sharpener of the type named above, so that a particularly simple construction and a simple, clear surface formation of the sharpener housing is possible in conjunction with the possibility of sharpening the points of pencils of different diameters.
In the case of a sharpener of the type named above, this objective is accomplished pursuant to the invention owing to the fact that it is constructed as a double sharpener with individual sharpeners for pencils of different diameters placed opposite to one another in a common housing and that the shape-cutting knives can be swiveled alternatively upward against the lead in the respective individual sharpener about a common axis, which is disposed at the common front end of the sharpener channels, which are open in the upward and downward directions in this region.
The inventive construction makes a very simple support possible with the help of a bearing shaft, which is integrally molded to the shape-cutting knife that preferably consists of plastic. Due to the inventive double sharpener construction, for which alternately one of the shape cutting knives makes contact from below with the respective sharpener knife, the two operating positions are also specified at the same time. In the one swiveling position, the shape-cutting knife of the one individual sharpener is in the operating position and the other is not. The reverse relationships are obtained by swiveling about the bearing axis. When the shape-cutting knife is swung out, the tip of the lead will be point-shaped and, when the shape-cutting knife is swung in, that is, in the quasi contacting position of the shape-cutting knife at the sharpener knife, the tip of the lead is shaped, that is, profiled with rounded end section.
In a development of the invention, a shape-cutting knife, consisting of plastic, can be offset by 180xc2x0 at a rotating shaft mounted laterally at the housing.
In a further development of the invention, the rotating shaft can be integrally molded with pivoted levers protruding up or down. These pivoted levers may preferably be constructed L-shaped with transverse legs, supported as stops, limiting the extent of swivel, on the upper edges or lower edges of the longitudinal walls of the housing.
This construction, with stops, limiting the extent of swivel, optionally enables the shape-cutting knife to be constructed in such a manner that it does not lie against the sharpener knives in the operating position and, instead, lies next to these precisely in the same cutting plane. This results in an optimal arrangement of the cutting edges of the shape-cutting knives with respect to the tip of the lead.
Instead of pivoted levers, adjusting knobs can also be provided on the rotating shaft to actuate the pivoting. This development of the invention can be realized particularly easily if the rotating shaft passes through vertical slots of the longitudinal walls of the housing, so that the rotating shaft with the integrally molded shape-cutting knives can be inserted very easily from above into the housing. In this connection, provisions are advantageously of course made so that, by locking stops somewhat overlapping the rotating shaft in the inserted position, an excessively easy unlocking in the upward direction is prevented. In the same way, it is advisably possible to provide locking catches, in order to lock the rotating shaft with the two shape-cutting knives in one of the two end positions set.
In a further development of the invention, the shape-cutting knives can be provided with bent cutting cross members, which correspond to the desired contour of the profiled lead and are essentially triangular in cross section, so that a true chip-removing cutting takes place and not merely a scraping of the tip of the soft lead, as a result of which an expensive cleaning with the help of cleaning rods or the like can be avoided after each profiling process.
Finally, it is also within the scope of the invention that the rotating shaft is seated with a bearing troughing on a lower, transverse partition of the sharpener channels.
Further advantages, distinguishing features and details of the invention arise out of the following description of an example as well as from the accompanying drawings.